a === b -> identical(a, b)

samples/swarm/App.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * The base class that should be extended by all HTML applications.
  *
  * It should both be easy to use for users coming over from JavaScript, but
  * also offer a clear notion of OO encapsulation.
  *
@@ skipping 46 matching lines @@
 
   /**
    * Erase the static splash screen.
    *
    * Assumption: if a splash screen exists, an element #appSplash contains it.
    */
   void eraseSplashScreen() {
     final splash = document.query("#appSplash");
     // Delete it if found, but it's okay for it not to be -- maybe
     // somebody just didn't want to use our splash mechanism.
-    if (splash !== null) {
+    if (splash != null) {
       splash.remove();
     }
   }
 
   /**
    * Swaps and reloads the app cache if an update is ready. Returns false if
    * an update is not ready.
    */
   bool swapAndReloadCache() {
     DOMApplicationCache appCache = window.applicationCache;
-    if (appCache.status !== DOMApplicationCache.UPDATEREADY) {
+    if (!identical(appCache.status, DOMApplicationCache.UPDATEREADY)) {
       return false;
     }
 
     print('App cache update ready, now swapping...');
     window.applicationCache.swapCache();
     print('App cache swapped, now reloading page...');
     window.location.reload();
     return true;
   }
 
@@ skipping 11 matching lines @@
       // TODO(jmesserly): Several problems with this:
       //   * How do we authenticate against the server?
       //   * How do we talk to a server other than thump?
       assert(url.startsWith('/'));
       return 'http://thump.googleplex.com$url';
     } else {
       return url;
     }
   }
 }